Regulator for compressors.



R. w. DOUGLASS. REGULATOR FOR COMPRESSORS.

APPLICATION FILED JULY 19, 1912.

Patented July 18, 1916 2 SHEETS-SHEET I gmoamtoz 33 1 GUM-11213 I, I @Q .2 3Q M1 R. DOUGLASS.

REGULATOR FOR-COMPR'ESSORS. I

APPLICATlON FILED JULY 19.1912.

"Patented July 18, 1916.

2 SHEETS SHEET 2.

m/vemtoz W U @151 Gum/14mg RICHARD w. DOUGLASS, or wnrrn' PLAms NEw YORK, ASSIGNOR 'ro INGERSOLII- RAND COMPANY, or NEW YO K, N.-

Y., A CORPORATION OF JERSEY.

REGULATOR FOR OOliIPRESSORSL Applicationfled July 19, 1912. Serial N 0. 710,371.

To all-whom it may concern Be it known that I, RICHARD W. Done- LASS, a citizen of the United States, residing at White Plains,'in the county of Westchester and State of. New York, have invented certain new and useful Improvements in Regulators for Compressors, of

.which the following is a specification.

This invent-ion relates to regulators for compressors and more particularly to regulators for continuously operated motor driven.

compressors'whereby the load on the compressor and hence the amount of ower used is regulated by controlling the discharge of the compressor into the receiving means. Regulators of this type are of various kinds, some reduce the load on the compressor by throwing in additional clearance atthe ends of the cylinder, others by varying the amount of air orother gas taken intothe compressor, others by closing off the intake of the compressor entirely, others by opening the discharge line of the compressor to the atmosphere rather. than to the receiving means; and still others by combination of two of these forms of unloaders. As ordi narily constructed these regulators or unloaders are arranged to operate when the pressure in the receiving means reaches a certain predetermined amount. It often happens however that, although a certain pressure is required, the full ca acity of the compressor is not required 7 or-extended periods of time and it is advisable under such conditions to o erate the compressor partially unloaded. ll the actual amount of power used will therefore be low. Where electricity is bought from a power company, however, in a majority of cases the charge for power is made up of a combination of two'charges, one based onthe actual consumption of electricityand the other based on the maximum amount used for a certain specified period, generally from three tofive minutes. With these ordinary forms of unloader-s although the average demand ma be considerably less than the capacity of t e compressor andhence will permit the compressor tojbe' unnder such conditions- -u nloading is accomplished by a clearance.

controller, a valve which clnses the intake to a'varying degree, or any other unloading rate of the second charge referred means which variably unloads the comv pressor, the desired result can be accomplished by limiting the action of theunloader "so that it never permits the capacity 'of the compressor to-go beyond a certain predetermined maximum. Where however the unloader is of the type which completely a discharge line unloader or an unloader completely closing of the intake of the compressor, or a combination of these, a different means of regulation must be resortedto and it is toward these types of unloaders that the present invention is p'rin-.

'. unloads the compressor such, as, for instance,

cipally directed although it is equally as well adapted for use with a var able unloaderif desired and such use is intended, to be covered b' the claims. With the ob ect above mentioned in view I have devised a regulating means, a prac-' tical embodiment. of which is shown in the accompanying drawings in connection with an unloader of the intake. closing type.

tion of a compressor showing my invention applied thereto, Fig. 2 is a section through the regulating means taken in" the line Ill-II of Fig. 3 and Fig 3 is a section at 'ri ht angles of Fig. 2 on the line III-III. v

he compressor as shown comprises a cylinder 1 provided with an inlet pipe 2 and a "discharge pipe 3. In the inlet pipe 2 is situated. an intake closing unloader of usual construction comprising-a valve 4: operated by a piston 5 wh ch slides in the cylinder 6. The valve 4 is closed by air from the disloaded for part of the time, still there are charge line of the compressor which is con- In the drawings: Figure l-is a side eleva- I apt to be temporary fluctuations in the" veyed to the cylinder 6 by a pipe 7, its addemand which will cause the compressor to operate at its full capacity for this specified period of time, or longer',thus incurring the mission to the cylinder 5 to unload thecom'. pressor being governed'by a diaphragm controlled need e valve 8 whichopensat a dismechanism, which is of well known construction the compressor is unloaded at a predetermined pressure in the discharge line which prevents the pressure in the receiver from becoming too great. I

In the present invention however there is an additional means for unloading the com-.- pressor. Opening directly into the cylinder 6 is a pipe which is periodically connected with the discharge line pipe 7 through a pipe 11 by the following mechanism. Pipes 10 and 11 both open into a valve chest 12, the. opening between them being controlled by a needle valve 13 which forms the lower end of a long valve rod 14. Valve rod 14 extends upwardly through a plug-15 into a casing 16, and is provided near its lower end with a flange 17 against which presses a spring 18 the upper endof' which contacts against the plug 15, th1s spring 18 serving tohold the valve in closed position. The valve rod 14 passes through and is adjustably secured by means of a screw 19 in a forwardly pro]ecting portion 20 of a rectangular yoke 21 which slides freely up and down in grooves 22 in the sides of. the casing 16. A periodical upward motion is given to this yoke 21 by means of a roller 23 secured by a pin 24 near the outer edge of a gear wheel 25. The roller 23 contacts with.

the upper cross bar during part of its revo-- lution thus raising the yoke and the valve rod 14 and opening the valve 13. The gear wheel 25 is actuated by a worm 26 which is in turn actuated by further reduction gearing comprising a gear wheel 27 and worm I 28. The worm 28 is actuated through a pulley 29 which is driven by a belt 30 from the" main shaft of the compressor.

In operation, supposing it weredesired to operate the compressor at half load, and ,the second power charge described above were calculated on the maximum amount of electricity taken, for any five minutes period, the reduction gearlng comprising the gears 25 and 27 and the worms 26 and 28- would-be so chosen thatthe gear 25 would wfmake a complete revolution in some period less than five minutes, say for instance one minute. Theyoke 21 would then be ad justed so that the roller 23 would contact with the upper cross-bar and lift .it from tion of the gear 25, thereby lifting the valve 13 from its'seat and establishin communication between pipes 10 and 11 or half the time. In this way the compressor would operate at full load during, the time the vatve 13, was closed and would be completely unloadedduring the'period that the valve 13 was open, connecting pipes 10 and 11 and allowing receiver pressure te. enter thecylinder, thus closing ofithe valve' 4= which. con;

.operation.

itsnormal position during half the I'QVOIH',

trols the intake to-the compressor. The compressor would therefore be alternately unloaded and fully loaded for' intervals of a half minute and would accordingly never operate at maximum capacity for any period as long as five minutes. Instead of half minute alternations the compressor might be of course run at full load for sayfour minutes and unloaded for a like time but in order to keep the receiver of reasonable size more frequent alternations are advisable as to prevent fluctuations in pressure in the receiver when the compressor is not furnishing air to it for such long periods, a receiver of large volume would be necessary. This periodical unloading in no way interferes with the normal unloading of the compressor which is occasioned by'the receiver pressure exceeding a predetermined amount. It is also evident that by varying the position of the yoke 21 the valve 13 can be kept open and the compressor run unloaded for any desired portion of the time, whileby changing the reduction gearing the period of al ternation can be changed.

It is to be understood that the present showing and description discloses only one specified modification of my invention and. other forms and modifications are included in the spirit and scope of the invention as expressed in the claims.

' WhatI claim is: i

1. In combination, a compressor, unloading means therefor, and means for operating said unloader at definite intervals irrespec- 100 tive of the compressing operation.

2. In combination, a compressor, driving means therefor, an unloader for said compressor, and means actuated by said driving means for operating said unloader at definite intervals irrespectlve of the compressing 3. In combinatioE-a' compressor, unloading means therefor, means for operating said unloader at definite intervals irrespec tive of the compressing operation and means for varying the duration of the operation of said unloading means.

4.. In combination, a compressor, driving means therefor, an unloader for said com- 5 pressor, means actuated by said driving means for operating said unloader for definite. periods at indefinite intervals irrespective of the compressing operation and means for varying the duration of saidperiods of operation.

5, In combination, a compressor, means for unloading said compressor comprising a fluid operated valve, and means for eriodi-' ucally admitting fluid to said un oading means to operate said valve.

" 6. In combination, a compressor, a drlving shaft therefor, a fluid operated unloadmagma speed reduction gearing connected with said driving shaft, and means actuated by said gearing toalternately open and close said valve.

8. In combination, a compressor, a fluid operated unloading means there for, a valve for admitting fluid. to said unloading means,

means to maintain said valve in open position for predetermined periods and means to vary the durationof said open periods.

9. In combination, a compressor, its driving'shaft, fluid operated unloading means for said compressor, a valve for admitting fluid to said unloading means, a reduction gearing connected with said driving shaft comprising a gear Wheel, valve, and means on said gear gwheel to periodically engage and operate said valve for predetermined periods to actuate said unloading means.

10. In combination, a compressor, a receiving means, means for unloading 'a compressor at a predetermined fluid pressure in said receiving means, and means independent of said fluid pressure for periodically unloading said compressor.

11. In combination, a compressor, a receiving means therefor, means for unloading said compressor, means controlled by the fluid pressure in said receiver for operating said unloading means, and. separate means for periodically operating said unloading means.

RICHARD W. DOUGLASS.

Witnesses:

A. M. HAYns, RALPH BURWELL Gooon. 

